An image apparatus user, such as a still or video camera user, often captures images that are blurred or shaky. The blurred or shaky images may be caused by a subject moving during image capture or by vibrations caused by the movement of the imaging apparatus itself during image capture. For example, camera shake, a slow shutter speed, or the use of a telephoto lens without a tripod can result in blurry or shaky images because the imaging apparatus moves during image capture.
An image stabilization technique is used to compensate for the motion of the imager during image capture. Image stabilization creates sharper images by dampening or counteracting the vibrations generated by the movement of the imaging apparatus or imager. One image stabilization technique employs a built-in gyro sensor to measure and correct for camera shake as it occurs. Another image stabilization technique uses an imaging sensor to capture images that are used to compensate for the motion of the imager.
FIG. 1 is a block diagram of a front view of an imaging apparatus according to the prior art. Imaging apparatus 100 includes imager 102 and motion sensor 104. As illustrated in FIG. 2, both imager 102 and motion sensor 104 capture images of scene 106. Motion sensor 104 captures images at a high frame rate and the motion of image apparatus 100 is calculated by correlating successive images of sensor 104. Motion sensor 104 has a smaller number of pixels compared to imager 102, resulting in sensor 104 having a smaller field of view 110 compared to imager 102. The smaller field of view 110 can cause motion sensor 104 to detect motion that occurs in scene 106 and incorrectly compensate for that motion rather than for any movement in the imaging apparatus. For example, motion sensor 104 may capture images of a person's head when imager 102 is capturing an image of a person. Motion sensor 104 will detect motion if the person moves his or her head during image capture. But imaging apparatus 100 may not have moved or may have moved less than the motion of the head. Thus, an image stabilization technique may incorrectly compensate for motion that did not occur in imaging apparatus 100, or overcompensate for motion in imaging apparatus 100.